This project is focused on determining how sound damage influences the expression pattern of neurotrophins and neurotrophin receptors in the adult mouse cochlear nucleus (CN). In order to make this determination, the expression pattern of molecules such as NT-3 and trkC must first be characterized in normally developing postnatal and adult animals. This projected was inspired by previous findings of this laboratory demonstrating that a response of the CN to noise damage is the infiltration of new axons into the damaged area and a body of literature indicating that neurotrophin could mediate such regrowth. Immunohistochemical analyses, using antibodies directed against proteins such as NT-3, trkC, SV-2, and NR1, of postnatal, adult, and noise-exposed adult animals will be conducted and the results compared for similarities and differences. [unreadable] [unreadable]